When artifacts of series resistance are eliminated, sodium gating current rises very rapidly, without a time delay. This implies that the gating current represents the movement of charge on the channel, itself, that occurs as part of the opening process. Our measurements of potassium accumulation are consistent with the view that previous measurements of a relatively slow rising phase were artifactual. Addition of ATP to the cytoplasm of the squid giant axon affects the behavior of the potassium current. The conductance-voltage curve becomes steeper and the conductance-time curve becomes slower.